The probability of a positive effect of carbon dioxide (CO(2)) gas on the physiologic oxidative lipolytic process led to its use for localized adiposities. The authors considered that existing studies on CO(2) therapy were not sufficient to exhibit the efficiency of CO(2) therapy. The scientific basis for evaluating CO(2) therapy including standard dietary regimen, standard daily physical effort, and standard psychosocial stimuli was not clear. Despite this unclear situation, CO(2) therapy is extremely popular worldwide. The authors designed an experimental study using histomorphologic examination and the laser-Doppler flow meter to monitor treated tissue in rats. They devised a controlled applicator device appropriate for gas injection of rats and compared biochemical effects between CO(2) and breathable air.